Draft-gear.



No. 759,572. PATENTBD MAY 10, 1904.

G. w. THOMPSON.

DRAFT GEAR.

APPLICATION FILED SEPT. 2, 1902. N0 MODEL. 2 SHEETS-SHEET 1.

M ATTORNEYS.

No. 759,572. PATENIED MAY 10, 1904.

' G. WITHOMPSON.

DRAFT GEAR.

APPLICATION FILED SEPT. 2, 1902.

N0 MODEL. 2 SHEETS-$3331 2.

522 Wm flfi 532 ATTORNEYS UNITED STATES Patented May 10, 1904.

PATENT OFFICE.

GRATTAN W. 'II-IOMPSON, OF ST. LOUIS, MISSOURI, ASSIGNOR TO PETER H.

MURPHY, OF EAST ST. LOUIS, ILLINOIS.

DRAFT-GEAR.

SPECIFICATION forming part of Letters Patent N0. 759,572, dated May 10,1904.

Application filed September 2, 1902. Serial Ne- 121,718. (No model.)

To (LZZ 1071 0772, it may concern:

Be it known that I, GEATTAN W. THOMPSON, a citizen of the United States,and a resident of the city of St. Louis and State of Missouri, 5 haveinvented a new and useful Draft-Gear,

of which the following is a speeiiicationl My invention relates todraft-gears for cars and locomotives, and has for its principal objectsto minimize the effects of sudden shocks IO and strains, to provide foran eflicient and increasing frictional resistance to the compression ofthe draft-gear and for the certain return thereof to normal positionwithout undesirable shock, and to attain advantages I5 hereinaftermentioned.

My invention consists in the construction hereinafter described andclaimed.

In the accompanying drawings, which form part of this specification, andwherein like 2 symbols refer to like parts wherever they occur, Figure 1is a side view of my draft-gear as applied to a railway-car, and Fig. 2is a plan view thereof. Fig. 3 is an end view of the inner cylinder.Fig. 1 is an end view of the 2 5 draft-gear assembled. Fig. 5 is a sideview of the inner cylinder. Fig. 6 is a longitudinal sectional view ofmy draft-gear with onehalf of the inner cylinder shown in elevation.Fig. 7 is a detail view of the end plate of the 3 inner cylinder; andFigs. 8, 9, 10, and 11 are detail views of the several friction-plates,respectively.

A. hollow cylindrical shell 1 is provided internally with a plurality ofhelical grooves or screw-threads 2 of high pitch. Asecond hollowcylindrical shell 3 is provided externally with helical ribs orscrew-threads 1, adapted to cooperate with the helical grooves of theouter cylinder 1. The outer end of the inner 4 cylinder has aninwardly-extending flange 5. Inside of the inner cylinder and restingagainst the end liange 5 thereof is a circular plate 6, which has a hub?projecting through and beyond the outer open end of the inner cylinder.This end plate 6 forms one abutment for one or more helical springs 8,extending through the inner cylinder. The

outer abutment for said spring or springs 8 consists of a fr1cti0n-p1eceor clutch 9, ar-

ranged near the inner end of the outer cylin- 5 der; This clutch orfriction-piece 9 1s a circular plate having on one side a central cymentthe threaded cylinder 3 is allowed a considerable longitudinal movementwithout becoming disengaged from the clutch or friction-piece 9.

The clutch or friction-piece 9 bears flatwise against a friction-plate14, which is made in 7 two sections and has a circular central open ing15 to permit it to iit over the circular hub 10 of the friction-piece 9.The periphery of this friction-plate 14: is provided with a series ofteeth 16, which interlock with teeth 17, provided therefor on the insideof the outer cylinder 1. For the double purpose of strengthening theteeth 17 and furnishing an abut ment for the friction-plate 14: thediameter of the outer shell beyond the screw-thread is reduced and theteeth 17 cut in the shoulder thus formed.

Abutting liatwise against the friction-plate 14 is a circularfriction-plate 18, which has a hole 19 therein of proper size and shapeto fit 8 5 over and interlock with the polygonal extension 11 of the hub10 of the clutch or frictionpiece 9. Preferably this extension 11 andthe hole 19 are rectangular; but other shapes adapted to interlock maybe used. On its 9 other side this friction-plate 18 abuts flatwiseagainst another friction-plate 20. This plate 20 is circular in form andhas two sets of lugs or teeth 21 22 on its periphery, which engz'ige insockets or notches provided therefor in a flange 23, arranged on theinside of the reduced end portion of the outer cylinder. One set of lugsor teeth 21 are the full thickness of the plate 20, and thecorresponding notches in the flange 23 extend through the full thicknessof the flange. The other set of teeth 22 are flush with the inner faceof the plate 20 and are only one-third the thickness thereof. Thenotches corresponding thereto are formed on the inner side of theperimeter of the flange 23 and extend only one-third the depth thereof.By this arrangement the bottoms of the shallow sockets form a stop orabutment to prevent the plate 20 falling out, but permit thefriction-plate 20 to project a slight dis tance through and beyond theend of the outer cylinder l,when the several friction-plates are jammedagainst each other. a

The construction hereinbefore described is mounted on the cars orlocomotive in the same general way as other draft-gears. As shown inFigs. 1 and 2, it rests between the upper and lower arms of a yoke 24,which is fastened to the draw-bar 25 of the car-coupler 26. Afollower-plate 27 intervenes between the drawbar 25 and one end of thedraft-gear, and a follower-plate 28 intervenes between the other endof'said draft-gear and the loop of the yoke 24:. These follower-plates27 and 28 are supported and mounted in any suitable manner, theirrespective movements being limited in one direction by ordinarydraft-lugs 29. The operation of my device is as follows: In the normalpositions of the draft-gear the plate 20 and the hub 7 of the plate 6project beyond the ends of the respective cylinders 1 and 3, being heldby the springs 8 against the respective follower plates 27 and 28. Whena pull is exerted upon a car-coupler 26, its force is transmittedthroughthe draw-bar 25 and yoke 2A and the follower-plate 28 against theprojecting hub 7 of the plate 6 at the end of the inner cylinder. As thefollower-plate 27 at the opposite end of the draftgear is prevented frommoving forwardly by reason of its contact with its draft-lugs 29 in itsnormal position, the pull transmitted through the yoke andfollower-plate 28, acting upon the hub 7, forces its plate 6 inwardlyagainst the force of the springs 8. W hen the hub has been forced inflush with the end of the inner cylinder, the continued pull forces theinner cylinder endwise' into the outer cylinder. The interlockingthreads permit this movement, but interpose a considerable resistancethereto in the form of friction. At the same time such threads cause arotary movement of the cylinders upon each other or of one cylinder uponthe other. As the friction-plates 14 and 20 are interlocked by teeth tothe outer cylinder 1 and the friction-plates 9 and 18 are interlocked bythe clutch and polygonal extension 11 of its hub 10 to the innercylinder 3, each of the four friction-plates has a motion transmitted toit from its corresponding cylinder, and the motion of each plate is inthe opposite direction to that of the friction-plate abutting againstit.

The friction thus caused by each friction-plate. grinding or sliding onits neighbor increases more and more as the pull increases and thesprings 8 are compressed thereby. WVhen the pull is released, the end ofthe plate 20 and the hub 7 on the end plates 6 are forced out beyond theends of the respective cylinders and the friction-plate 14, is forcedback against the shoulder or abutment provided therefor on the inside ofthe outer cylinder. The pressure of the spring is thereby cut off fromthe remaining friction-plates 18 and 20, so that the friction-plate 18rests loosely between the plates 14: and 20, and the friction caused byits rotation is very slight and negligible. In order to restore thedraft-gear to its normal position, therefore, the spring merely has toovercome the friction between the clutchplate 9 and the plate 14 and thefriction between the screw-threads -2 and 4. In order to reduce thelatter, those faces 30 of the threads which are working when thedraftgear is being returned to normal position are arranged at rightangles to the axis thereof, whereas the other meeting faces 31 (whichare the working faces when the spring is being compressed) are arrangedat a comparatively small angle to the axis, so as to wedge more tightlytogether in operation. In order to reduce the area of the surfaces incontact during the retracting movement, it is desirable to true up orfinish the square faces 30 for only aportion of the length of thethread, the remaining portion being undercut to render it inoperative.It is also desirable to make the threads fit loosely, so as to allow aslight endwise play of the cylinders. In operation the spring upon therelease of the pull which compressed it will force the plate 6 againsttheend flange 5 of the inner cylinder with a sudden shock, which aidsconsiderably in loosening the two cylinders and starting their returnmovement.

IVhen the gear is required to resist a buffing force, its operation issimilar to that above described with reference to the pulling force,except that the follower-plate 27 moves and the follower-plate 28 isstationary during the buffing action. Consequently the draft-gearconstitutes a bufiing apparatus and is capable of use as suchindependently of its function as a draft-gear, and I do not wish torestrict myself to the use thereof in connection with railway-cars andlocomotives.

Obviously the construction hereinbefore described admits of considerablemodification without departing from my invention. For instance, thefriction-plate 14 may be formed with its outer face hollowed outconically, and the plate 18 may be formed with its inner face projectingconically, in which case the hub 10 practically disappears and the polyonal extension 11 is formed directly on the plate 9. So, also, thefriction-plates may be eliminated and the friction of the helical guidesor ribs alone relied on for the resistance. In such case two innercylinders interlocked by longitudinally-extending arms and threaded withthe same or different pitches may be made to work in correspondingthreads in the inner cylinders, and the spring may abut against theclosed ends of these inner cylinders.

WVhat I claim is 1. A railway draft-gear comprising two cylindersprovided with internal and external helical guides of steep pitcharranged to cooperate and a spring tending to separate said cylindersendwise and arranged to turn bodily with the inner cylinder.

2. A railway draft-gear comprising two cylinders provided with internaland external helical guides of steep pitch arranged to cooperate, and aspring tending to separate said cylinders endwise, said guides beingarranged throughout their entire length to permit a slight endwise playof the cylinders.

3. A railway draft-gear comprising two cylinders provided with internaland external threads of steep pitch arranged to cooperate, and a springtending to separate said cylinders endwise, the faces of said threadswhich are working on the return movement of the draft-gear beingsubstantially perpendicular to the axis and the other faces beingconsiderably inclined thereto.

4. A railway draft-gear comprising two cylinders provided withcooperating internal and external helical guides of high pitch, theinner cylinder having longitudinally projecting arms at its inner endand a clutch-plate having arms to interlock therewith, and a pluralityof friction-plates arranged to interlock with the outer cylinder andsaid clutch-plate respectively and arranged to be jammed flatwisetogether, and a spring tending to separate said cylinders endwise,substantially as described.

5. A railway draft-gear comprisingtwo cyl inders provided respectivelywith internal and external helical ribs of steep pitch arranged tointerlock, a plurality of friction-plates arranged to be jammed togetherflatwise and. the abutting plates being fastened to move withdiiferentcylinders, substantially as described.

6. A railway draft-gear comprising two cylinders provided respectivelywith internal and external helical ribs of steep pitch arranged tointerlock, a plurality of friction-plates arranged to be jammed togetherflatwise and the abutting plates being fastened to move with differentcylinders, and a spring bearing against the innermost friction-plate anda piece at the opposite end of the inner cylinder, substantially asdescribed.

7. A railway draft-gear comprising two cylinders provided respectivelywith internal and external helical ribs of steep pitch arranged tointerlock, a plurality of friction-plates arranged to be jammed togetherfiatwise and the abutting plates being fastened to move with differentcylinders and a longitudinally-mov able end plate for the opposite endof the inner cylinder having a hub normally projecting beyond said end,and a spring bearing against said end plate and the innermostfrictionplate, substantially as described.

8. A railway draft-gear comprising two cylinders provided withinterlocking guides of steep pitch, an inner shoulder near the end ofthe outer cylinder, a longitudinally-movable friction-plate adapted toabut endwise against said shoulder but locked against rotary movementrelative to said outer cylinder, a longitudinally-movable friction-platearranged to project beyond the end of the outer cylinder, and one ormore friction-plates between said above-mentioned plates, alternatefrictionplates being fastened to rotate with the respective cylinders,and a spring tending to separate said cylinders endwise, substantiallyas described.

9. Arailway draft-gear comprisingtwo cylinders provided withinterlocking helical guides of a steep pitch, a shoulder inside of saidouter cylinder near the end thereof, a longitudinally-movablefriction-plate adapted to abut against said shoulder but interlockedwith said outer cylinder to move therewith, a longitudinally-movablefriction-plate arranged to project beyond the end of the outer cylinderbut interlocked to rotate therewith, a longitudinally movable clutchpiece interlocked with the inner cylinder to rotate therewith, and alongitudinally -movable friction-plate between said above-mentionedfriction-plates and interlocked with said clutch to rotate with theinner cylinder, and a longitudinally-movable end plate for the outer endof the inner cylinder having ahub projecting beyond the end thereof. anda spring bearing against said clutch-piece and said end plate,substantially as described.

10. A railway draft-gear comprising two cylinders provided withinterlocking helical guides of steep pitch, a shoulder inside of saidouter cylinder near the end thereof, a longitudinally-movablefriction-plate adapted to abut against said shoulder but interlockedwith said outer cylinder to move therewith, a longitudinally-movablefriction-plate arranged to project beyond theend of the outer cylinderbut interlocked to rotate therewith, a longitudinally-movableclutch-piece interlocked. with the inner cylinder to rotate therewith,and a longitudinally-movable frictionplatc between said above-mentionedfrictionplates and interlocked with said clutch to rotate with the innercylinder, and a spring tending to separate said cylinder endwise,substantially as described.

11. A railway draft-gear comprising two cylinders provided withinterlocking helical guides of steep pitch, a shoulder inside of saidouter cylinder near the end thereof, a longitudinally-movablefriction-plate adapted to abut against said shoulder but interlockedwith said outer cylinder to move therewith,

a longitudinally-movable friction-plate arranged to project beyond theend of the outer cylinder but interlocked to rotate therewith, and aclutch consisting of a friction-plate having on one side arms adapted tointerlock with longitudinallyextending arms on the inner cylinder andhaving on the other side a central hub extending through thefirst-mentioned friction-plate with a polygonal extension thereon, alongitudinally-movable fricouter cylinder but interlocked to rotatetherewith, a longitudinally-movable clutch-piece interlocked with theinner cylinder to rotate therewith, and a longitudinally-movablefriction-plate between said above-mentioned friction-plates andinterlocked with said clutch to rotate with the inner cylinder, and alongitudinally-movable end plate for the outer end of the inner cylinderhaving a hub projecting beyond the end thereof, and a spring bearingagainst said clutch-piece and said end plate, substantially asdescribed.

13. A railway-gear comprising two cylinders provided with cooperatinginternal and external helical guides of steep pitch, the inner cylinderhaving longitudinally-projecting arms at its inner end, and a platehaving arms to interlock therewith, and a spring bearing endwise againstsaid plate and the opposite end of the inner cylinder, andfriction-plates arranged to cooperate with said cylinders.

St. Louis, Missouri, August 30, 1902.

GRATTAN XV. THOMPSON.

WVitnesses:

JAMES A. CARR, WILLIAM P. CARR.

